1. Field of the Invention
The present invention relates to an electric rotating machine such as motor and, more particularly, to a small-sized electric rotating machine that includes a rotational position detector and a switching element part controlling current flowing through the electric rotating machine, and that is suitably mounted occupying a small space such as for use in vehicles.
2. Description of the Related Art
In an electric motor integrated with a control device that is disclosed, for example, in the Japanese Patent Publication (unexamined) No. 27903/1999 (on pages 4-5, FIG. 2), a control device case is fixed to an end bracket or to a housing on the side opposite to the load of an electric motor, and a cooling fan is attached to an end portion on the side opposite to the load of a shaft running through the control device case. The control device case contains an inverter circuit and a positional detector of a rotor that is located on the inner circumferential side of the inverter circuit.
Outputs from the electric motor are adjusted by ON/OFF control of a switching element of the inverter circuit. When operating the switching element, sharp magnetic field change occurs accompanied by the rapid change of currents, and therefore such magnetic field change comes out as electromagnetic noises in other devices or circuits, which may lead to the occurrence of malfunction.
In the electric motor integrated with a control device as disclosed in the above-mentioned Japanese Patent Publication (unexamined) No. 27903/1999, since the inverter circuit part containing the switching element and the rotational position detector of the rotor are disposed in proximity to each other, noises that are generated by the above-mentioned sharp change of magnetic field are superimposed on the output from the rotational position detector. Consequently, a problem exists that the position of the rotor is erroneously detected.